The long range purpose of this project is to understand the regulation of cellular proliferation and differentiation in oral-facial and limb tissue by: (1) defining the factors involved in the in vitro differentiation of cranial neural crest cells; (2) developing procedures to culture the rodent embryo during the time of primary and secondary palatal development; (3) determining the biochemical events that regulate palatal epithelial cell adhesion and death; (4) defining the molecular basis for sensitivity to glucocorticoid-induced cleft palate; and (5) determining the key biochemical events during normal and abnormal chondrogenesis. BIBLIOGRAPHIC REFERENCES: Hassell, J.R. and Pratt, R.M.: Elevated levels of cAMP alters the effect of EGF in vitro on programmed cell death in secondary palatal epithelium. Ex. Cell Res. 106: 55-62, 1977. Morgan, P.R. and Pratt, R.M.: An ultrastructural study of the effect on DON on the secondary palatal epithelium in vivo. Teratology 15: 281-290, 1977.